1. Field of the Invention
This invention relates generally to the field of dental positioning systems for electronic and film x-ray examinations, and more particularly to a dental positioning system for positioning and aligning dental films and electronic x-rays sensors using adhesives.
2. Related Art
Intra-oral x-rays are an important aspect of dental care. Such x-rays have many uses, including diagnosing cavities and lesions, documenting treatment, and assisting in guiding procedures, among other things. Radiographs obtained using x-rays may be taken using either x-ray sensitive film or an x-ray sensitive electronic image sensor, such as a digital image sensor, as the image receptor. In either case, the receptor must be placed in the mouth and carefully aligned such that the x-rays emanating from the x-ray source are incident upon it. For example, in many applications it is desirable for the receptor to be positioned such that it is perpendicular to the x-ray beam. In any event, if the receptor is not placed and aligned correctly in the patient""s mouth, clinically usable images generally may not be obtained.
Because of the need for accurate positioning, and because of the inherent difficulties involved, several devices have been proposed to assist dental practitioners in placing and aligning the receptor. Speaking generally, such devices are designed to grip the receptor and to have a bite area such that when the patient engages his or her teeth on the device, the device attempts to urge the receptor into the proper position. Some devices also have attachments which protrude from the mouth and give the practitioner an alignment point so that he or she can properly position the x-ray source.
In the specific case of digital radiology, a solid state image sensor (such as, for example, an image sensor comprising a charge-coupled device (CCD) or a CMOS active pixel sensor array (APS)) is used in place of film. Such sensors are typically 5-6 mm thick, and often have a cable which delivers the image from the sensor to a processing unit, such as a computer. The positioning devices used for such electronic sensors should grip the sensors quite firmly in order to ensure that they are not moved out of position by the tension on the cable. Moreover, electronic sensors, unlike pieces of film, are re-usable, and therefore should preferably be covered by a sterile infection barrier, such as a sheath. As a result, the conventional devices used to position electronic sensors tend to mechanically grip the sensor around its edges.
Although prior art techniques are generally good for their intended purposes, there are several problems with existing dental x-ray positioning systems, with respect to both film and electronic receptors, which are not addressed adequately by these techniques. One problem is that the gripping device presents distinct protrusions around the edges of the receptor. These protrusions can be quite uncomfortable to the patient and may even injure the patient if they become sharp.
Another problem is that the existing holder systems present a fixed relationship between the receptor and the bite area, thereby allowing very little flexibility of placement. That is, because the anatomy of the mouth varies between patients, the user has very little flexibility in how the receptor will be positioned relative to the teeth being imaged. This is a significant drawback, since it may be difficult or impossible to achieve a useful image without some flexibility in the positioner. This may lead not only to sub-optimal coverage of dental anatomy, but also to patient discomfort, due to the presence of sharp edges in film packaging or by the lack of degrees of freedom provided by the holders. Prior attempts to improve upon patient comfort included providing a cushioned package. Some examples of a cushioned system include U.S. Pat. No. 4,912,740 to Liese, Jr.; U.S. Pat. No. 5,044,008 to Jackson; and U.S. Pat. No. 6,062,730 to Sims et al. Such systems, however, resulted in only limited improvements because even if the device is soft, if it is forced into position, it can nonetheless be uncomfortable to the patient.
U.S. Pat. No. 4,866,750 to Chavarria discusses an image receptor holder on a multi-dimension stage. The device allows for horizontal and vertical movement of the image receptor with respect to the x-ray source, so that the device may be adjusted somewhat to accommodate the contours of a particular patient""s mouth. However, while this system may in theory allow some flexibility in placement, it is impracticable to utilize it in a clinical environment due to its large and bulky structure, which can make it difficult to adjust the device as needed.
Another problem is that receptors may vary in dimension, either due to manufacturing variations or due to the existence of various sizes of receptors. Film, for example, is available in size 2 (bitewing), size 1 (anterior) and size 0 (pediatric), among other sizes, and many electronic sensors are available in corresponding sizes. Because of these variations, a unique gripping device should be used for each exact size of sensor, which introduces additional complications to the process.
Another problem is that the gripping devices will fatigue if used repeatedly, thereby limiting their useful life.
One problem specific to electronic sensors is that because the gripping device should make very tight contact with the sensor, the sterile sheath may be torn, thus contaminating the sensor or even damaging the sensor itself through mechanical fatigue. This is highly problematic, as an electronic sensor is a relatively costly item, typically on the order of several thousands of dollars.
There is a need, therefore, for an x-ray positioning system that departs significantly from the conventional methodologies, takes an entirely fresh approach towards solving the problems discussed above, and provides a simple and effective way of positioning and aligning both film and electronic sensors.
Accordingly, it is an object of this invention to provide a dental x-ray positioning system which overcomes the above-mentioned problems. More specifically, it is an object of this invention to provide a positioning system wherein the positioning device connects to the receptor by attaching to an adhesive coating. In this way, the receptor is bonded to a holder in a convenient location and orientation. The adhesive coating may be on the positioning device or on the receptor.
It is also an object of this invention to provide a novel holder system for positioning and aligning dental x-ray films or sensors. The system uses an adhesive to bond the holder to an encapsulated film or sensor.
It is also an object of this invention to provide a positioning system wherein there are no uncomfortable holding tabs, protrusions, or protruding edges associated with the receptor.
It is also an object of this invention to provide a positioning system wherein the positioning device or positioner may be attached to the receptor at any point along the surface, thereby maximizing positioning flexibility.
It is also an object of this invention to provide a positioning system wherein the positioning device and the receptor are removably attached to each other by the adhesive.
It is also an object of this invention to provide a positioning system wherein the same positioner may be used with receptors of any dimension.
It is also an object of this invention to provide the clinician with a greater freedom of positioning to improve upon patient comfort.
A system for dental x-ray examinations according to one embodiment of this invention comprises an image receptor and a holder removably bonded to the image receptor by an adhesive coating on a surface of the holder. The image receptor may comprise film or an electronic sensor. If the image receptor is an electronic sensor, the electronic sensor may comprise a CMOS active pixel sensor array or a charge-coupled device.
Another embodiment of this invention provides a holder for a dental image receptor having an adhesive coating to removably bond the holder to the dental image receptor.
A system for dental x-ray examinations according to one embodiment of this invention comprises an image sensor, a sheath covering the image sensor, and a holder having an adhesive coating and bonded to the sheath by the adhesive coating. The holder may be bonded to the sheath at any point along a surface of the image sensor.
The image sensor may comprise a charge-coupled device or a CMOS active pixel sensor array. The sheath may be a material selected from the group comprising paper, cotton, sponge, rubber, plastic, latex, and nylon. The adhesive may be selected from the group comprising tape, epoxy, hot melt, and sealant.
A system for dental x-ray examinations according to another embodiment of this invention comprises an image sensor, a sheath covering the image sensor, an adhesive coating on the sheath, and a holder bonded to the sheath by the adhesive coating.